In general, a rubber composition having an additive compounded in a nitrile rubber is used for an elastic member used for a sealing device which is used for a rolling bearing for automobile wheels. However, since the rolling bearing for automobile wheels is used outdoors, it may be exposed to a large quantity of dusts or splashed with rainwater or water when washed, and furthermore, it may be dipped in muddy water. As a sealing device having a good sealing property even in such a severe state, there is proposed a sealing device having an elastic member made of a vulcanizable rubber composition having carbon black compounded in a carboxylated acrylonitrile butadiene rubber (see, for example, Patent Document 1).
Patent Document 1: JP-A-2002-372062